Refereeing Out of Pitch
Overview
Refereeing out of pitch is enabled when the following conditions are met:
1. Drone Position is known.
2. Drone is inside the Pitch.
3. The ball has been detected.
4. The Lines have been detected, filtered and matched with the outer model lines references.
Relations:
- The Localization skill covers conditions 1 and 2.
- Condition 3 is covered by the Ball Detection sub-task.
- Condition 4 is covered by matching the output lines from Line Detection sub-task with the output from the Field Line predictor.
Once all conditions are met the refereeing enables. The process of refereeing involves computer vision only. Conditions 1 and 2 are needed to enable refereeing but the outputs from 3 and 4 are the ones used for the actual refereeing.
Refereeing Method
The process of refereeing is explained as follows:
First, we assume that the drone position within the frame will be the center taking into account that the pitch and roll of the drone will be near zero and the camera FOV has a pitch of pi/2 rad (completely vertical).
Second, the ball position (center) and the outer lines detected within the frame are provided by 3 and 4.
Third, we defined different areas on the frame based on the relative position to the outer lines. The defined areas are assigned with a combination of a binary output stating if a point is below (‘0’) or above (‘1’) that line (For that purpose, completely vertical lines are filtered and are given a nearly vertical slope), e.g. if we are seeing only 1 outer line in the frame this binary output will be composed of only one ‘bit’, if we are seeing two (a corner) it will be composed of ‘2’ bits, etc.
Finally, we calculate the relative drone position (given it is inside the pitch as an enabling condition for refereeing) to the outer lines and we select that area as the ‘In pitch’ area. Then, we calculate the ball relative position to the outer lines and check if it is ‘In Pitch’ (same area as the drone) or ‘Out of Pitch’. (any of the other defined areas in the frame)
Out of pitch Refereeing output
The Out of Pitch refereeing sub-task outputs the flag with the status 'In Pitch' (0), 'Out of pitch' (1) or 'Not Known' (-1) in the case the conditions for refereeing are not met.